The first step in getting started with C# WeChat development

/// <summary>
 /// 验证微信签名
 /// </summary>
 /// <returns></returns>
 /// * 将token、timestamp、nonce三个参数进行字典序排序
 /// * 将三个参数字符串拼接成一个字符串进行sha1加密
 /// * 开发者获得加密后的字符串可与signature对比，标识该请求来源于微信。
 private bool CheckSignature()
 {
 var token = "token"; 
 var signature = HttpContext.Current.Request.QueryString["signature"];
 var timestamp = HttpContext.Current.Request.QueryString["timestamp"];
 var nonce = HttpContext.Current.Request.QueryString["nonce"];
 var echostr = HttpContext.Current.Request.QueryString["echostr"];
 string[] ArrTmp = { token, timestamp, nonce };
 Array.Sort(ArrTmp); //字典排序
 var tmpStr = string.Join("", ArrTmp);
 tmpStr = FormsAuthentication.HashPasswordForStoringInConfigFile(tmpStr, "SHA1");//加密方式

 if (tmpStr.ToLower() == signature)
 {
 return true;
 }
 return false;
 }

 #region 接收消息
 /// <summary>
 /// 接收微信发送的XML消息并且解析
 /// </summary>
 private void ReceiveXml()
 {
 var requestStream = HttpContext.Current.Request.InputStream;
 var requestByte = new byte[requestStream.Length];
 requestStream.Read(requestByte, 0, (int)requestStream.Length);
 var requestStr = Encoding.UTF8.GetString(requestByte);

 if (!string.IsNullOrEmpty(requestStr))
 {
 //封装请求类
 var requestDocXml = new XmlDocument();
 requestDocXml.LoadXml(requestStr);
 var rootElement = requestDocXml.DocumentElement;
 if (rootElement == null) return;
 var wxXmlModel = new WxXmlModel
 {
  ToUserName = rootElement.SelectSingleNode("ToUserName").InnerText,
  FromUserName = rootElement.SelectSingleNode("FromUserName").InnerText,
  CreateTime = rootElement.SelectSingleNode("CreateTime").InnerText,
  MsgType = rootElement.SelectSingleNode("MsgType").InnerText
 };

 switch (wxXmlModel.MsgType)
 {
  case "text"://文本
  wxXmlModel.Content = rootElement.SelectSingleNode("Content").InnerText;
  break;
  case "image"://图片
  wxXmlModel.PicUrl = rootElement.SelectSingleNode("PicUrl").InnerText;
  break;
  case "event"://事件
  wxXmlModel.Event = rootElement.SelectSingleNode("Event").InnerText;
  if (wxXmlModel.Event != "TEMPLATESENDJOBFINISH")//关注类型
  {
  wxXmlModel.EventKey = rootElement.SelectSingleNode("EventKey").InnerText;
  }
  break;
  default:
  break;
 }

 ResponseXML(wxXmlModel);//回复消息
 }
 }
 #endregion

 #region 回复消息
 private void ResponseXML(WxXmlModel WxXmlModel)
 {
 var QrCodeApi = new QrCodeApi();
 var XML = "";
 switch (WxXmlModel.MsgType)
 {
 case "text"://文本回复
  XML = ResponseMessage.GetText(WxXmlModel.FromUserName, WxXmlModel.ToUserName, WxXmlModel.Content);
  break;
 case "event":
  switch (WxXmlModel.Event)
  {
  case "subscribe":
  if (string.IsNullOrEmpty(WxXmlModel.EventKey))
  {
  XML = ResponseMessage.GetText(WxXmlModel.FromUserName, WxXmlModel.ToUserName, "关注成功");
  }
  else
  {
  XML = ResponseMessage.SubScanQrcode(WxXmlModel.FromUserName, WxXmlModel.ToUserName, WxXmlModel.EventKey);//扫描带参数二维码先关注后推送事件
  }
  break;
  case "SCAN":
  XML = ResponseMessage.ScanQrcode(WxXmlModel.FromUserName, WxXmlModel.ToUserName, WxXmlModel.EventKey);//扫描带参数二维码已关注 直接推送事件
  break;
  }
  break;
 default://默认回复
  break;
 }
 HttpContext.Current.Response.Write(XML);
 HttpContext.Current.Response.End();
 }
 #endregion